Growing evidence suggests that cardiovascular disease (CVD) morbidity and mortality may be predicted not only by established risk factors such as cholesterol level, hypertension, cigarette smoking, and hyperglycemia, but also by a set of emerging risk factors. These include the inflammatory markers, C reactive protein and interleukin 6, metabolic syndrome, and mild renal insufficiency. A project called HeartSCORE funded by the Commonwealth of Pennsylvania (Steven Reis, PI) is evaluating these emerging risk factors as well as coronary calcification, and brachial artery diameter in a population-based sample of 1000 African Americans and 1000 Caucasians. Our proposed project will build on this invaluable resource by examining another set of novel risk factors for CVD thought to be upstream from the more proximal, emerging risk factors: sleep disordered breathing (SDB) and psychosocial stress. Our project will evaluate whether links of both SDB and psychosocial stress with CVD risk may be due to their effects on nocturnal physiology, namely altered nonSDB sleep characteristics, nighttime elevation in blood pressure relative to daytime BP (termed nondipping), elevated urinary catecholamines and cortisol, and impaired autonomic tone. Thus, the general aim of this study is to understand the nocturnal psychophysiological underpinnings of cardiovascular morbidity and mortality. To address this general aim, we will study a multi-ethnic sample of 225 individuals drawn from two of the groups in the larger HeartSCORE design: (1) those who have high/moderate (hereafter labeled high) or (2) low Framingham risk equation scores, with no history of stroke, myocardial infarction, or interventional cardiology procedures in either group. The two groups will be matched on gender, race, and age. The proposed study will include two nights of polysomnography (PSG) conducted in participants' homes, two 24-hour periods of ambulatory blood pressure (ABP) monitoring, overnight urine collections on PSG night 2 and ABP night 2, wrist actigraghy on 10 nights, and assessment of self-report and other physiological indices. The study will provide novel data testing the relationships of daytime stressful events, SDB, and other nocturnal physiological measures with the emerging risk factors and subclinical CVD measured in HeartSCORE. [unreadable] [unreadable]